Chip design
The chip design is a rectangular design for electronic components, mostly resistors or capacitors , which belong to the group of surface mounted devices . The designation of the designs almost always consists of four digits. The first two indicate the housing size between the two connections, the last two the size of the component on one connection side. The unit is often 1 ⁄ 100 inches (= 10 mil = 0.254 mm). Alternatively, some manufacturers (e.g. Susumo, TDK, GTLight) give the dimensions in units of 1 ⁄ 10 mm instead . The side on which the metal connection caps are located is usually the shorter side (broad side; see pictures). With an 1812 component, the connections are therefore on the shorter side, while with a 1218 component they are on the longer side (however, both components are the same size). Chip components are used in large numbers in electronic devices. Due to their low price, easy processing and small size, they are also known in technical jargon as "chicken" or "bird food".
Packaging and processing
Since the components are very small and usually larger numbers are required, they are packed in cardboard or plastic belts. There are pockets in the straps in which the components are located; the top of the pocket is closed by a film that can be pulled off to remove the component. The straps themselves are wound onto a roll. On at least one side, the roller has holes at regular intervals with which the belt can be moved by the pick and place machine . The whole thing is similar to films on a roll of film.
The rollers are set up on special feeders , which are inserted into the placement machines. These then each remove a component with vacuum tweezers and place it on the assembly (pick and place). There are rolls with different quantities, for example 2500, 5000, 10000 or 15000 pieces.
| Size code (inch) according to EIA standard |
length in mm | Width in mm | Length in inches | Width in inches |
|---|---|---|---|---|
| 01005 | 0.4 | 0.2 | 0.016 ± 0.0008 | 0.008 ± 0.0008 |
| 0201 | 0.6 | 0.3 | 0.024 ± 0.002 | 0.012 ± 0.001 |
| 0402 | 1.02 ± 0.10 | 0.50 ± 0.10 | 0.040 ± 0.004 | 0.020 ± 0.004 |
| 0504 | 1.27 ± 0.15 | 1.02 ± 0.15 | 0.050 ± 0.006 | 0.040 ± 0.004 |
| 0603 | 1.60 ± 0.10 | 0.80 ± 0.10 | 0.063 ± 0.004 | 0.031 ± 0.004 |
| 0805 | 2.00 ± 0.15 | 1.25 ± 0.15 | 0.079 ± 0.006 | 0.050 ± 0.006 |
| 0907 | 2.29 ± 0.20 | 1.78 ± 0.20 | 0.090 ± 0.008 | 0.070 ± 0.008 |
| 1008 | 2.50 ± 0.15 | 2.00 ± 0.15 | 0.098 ± 0.006 | 0.078 ± 0.006 |
| 1206 | 3.20 ± 0.15 | 1.60 ± 0.15 | 0.126 ± 0.006 | 0.063 ± 0.006 |
| 1210 | 3.20 ± 0.15 | 2.50 ± 0.15 | 0.126 ± 0.006 | 0.098 ± 0.006 |
| 1411 | 3.50 ± 0.20 | 2.80 ± 0.20 | 0.138 ± 0.008 | 0.110 ± 0.008 |
| 1515 | 3.81 ± 0.38 | 3.81 ± 0.38 | 0.150 ± 0.015 | 0.150 ± 0.015 |
| 1608 | 4.00 ± 0.20 | 2.00 ± 0.20 | 0.157 ± 0.008 | 0.078 ± 0.008 |
| 1812 | 4.60 ± 0.20 | 3.20 ± 0.20 | 0.181 ± 0.008 | 0.126 ± 0.008 |
| 1825 | 4.60 ± 0.20 | 6.30 ± 0.20 | 0.181 ± 0.008 | 0.248 ± 0.008 |
| 2010 | 5.08 ± 0.13 | 2.54 ± 0.08 | 0.200 ± 0.005 | 0.100 ± 0.003 |
| 2220 | 5.70 ± 0.20 | 5.00 ± 0.20 | 0.224 ± 0.008 | 0.197 ± 0.008 |
| 2312 | 6.00 ± 0.20 | 3.20 ± 0.20 | 0.236 ± 0.008 | 0.126 ± 0.008 |
| 2512 | 6.35 ± 0.13 | 3.20 ± 0.08 | 0.250 ± 0.005 | 0.126 ± 0.003 |
| 2515 | 6.30 ± 0.20 | 3.81 ± 0.20 | 0.248 ± 0.008 | 0.150 ± 0.008 |
| 2716 | 7.00 ± 0.20 | 4.00 ± 0.20 | 0.275 ± 0.008 | 0.157 ± 0.008 |
| 2824 | 7.20 ± 0.20 | 6.10 ± 0.20 | 0.283 ± 0.008 | 0.240 ± 0.008 |
| 2917 | 7.30 ± 0.20 | 4.30 ± 0.20 | 0.287 ± 0.008 | 0.170 ± 0.008 |
| 2920 | 7.30 ± 0.20 | 5.00 ± 0.30 | 0.287 ± 0.008 | 0.197 ± 0.012 |
| 3111 | 8.00 ± 0.20 | 2.80 ± 0.20 | 0.315 ± 0.008 | 0.110 ± 0.008 |
| 3931 | 10.00 ± 0.20 | 8.00 ± 0.20 | 0.394 ± 0.008 | 0.315 ± 0.008 |
| 4018 | 10.16 ± 0.20 | 4.60 ± 0.20 | 0.400 ± 0.008 | 0.181 ± 0.008 |
| 4040 | 10.2 ± 0.50 | 10.2 ± 0.50 | 0.400 ± 0.020 | 0.400 ± 0.020 |
| 4320 | 11.00 ± 0.20 | 5.00 ± 0.20 | 0.433 ± 0.008 | 0.197 ± 0.008 |
| 4335 | 11.00 ± 0.20 | 9.00 ± 0.20 | 0.433 ± 0.008 | 0.352 ± 0.008 |
| 4349 | 11.00 ± 0.20 | 12.50 ± 0.20 | 0.433 ± 0.008 | 0.492 ± 0.008 |
| 4424 | 11.10 ± 0.81 | 6.10 ± 0.40 | 0.435 ± 0.032 | 0.240 ± 0.015 |
| 4527 | 11.50 ± 0.20 | 7.00 ± 0.20 | 0.455 ± 0.008 | 0.275 ± 0.008 |
| 4540 | 11.4 ± 0.58 | 10.2 ± 0.50 | 0.450 ± 0.023 | 0.400 ± 0.020 |
| 4723 | 12.00 ± 0.20 | 6.00 ± 0.20 | 0.472 ± 0.008 | 0.236 ± 0.008 |
| 4825 | 12.20 ± 0.20 | 6.35 ± 0.20 | 0.480 ± 0.008 | 0.250 ± 0.008 |
| 5550 | 14.00 ± 0.71 | 12.70 ± 0.63 | 0.550 ± 0.028 | 0.500 ± 0.025 |
| 5727 | 14.40 ± 0.20 | 7.00 ± 0.20 | 0.567 ± 0.008 | 0.275 ± 0.008 |
| 6145 | 15.50 ± 0.20 | 11.50 ± 0.20 | 0.610 ± 0.008 | 0.455 ± 0.008 |
| 6561 | 16.50 ± 0.20 | 15.50 ± 0.20 | 0.651 ± 0.008 | 0.610 ± 0.008 |
| 7565 | 19.10 ± 0.96 | 16.50 ± 0.83 | 0.750 ± 0.038 | 0.650 ± 0.033 |
The height of the components is not standardized, but it is usually the same for resistors, while for capacitors it can vary greatly depending on the manufacturer, capacitance and dielectric strength.
processing
SMD components are intended for machine assembly, but can also, for. B. processed manually by hot air soldering with a hand-held device.
Wave soldering is possible down to size 0805 . To do this, the components must be glued in place during assembly, as shown in the photo. It is inexpensive, especially with mixed assemblies.
Smaller sizes require reflow soldering . Adhesive dots are then only required for double-sided SMD assembly, or the circuit board design and soldering process are designed so that the components on the underside do not fall off.